Biodiversity of the Loddon Campaspe Irrigation Region

Note Number: LC0436
Published: May 2008
Stacey Warmuth, Kerang
ISSN 1329-833X

The Loddon Campaspe Irrigation Region (LCIR) supports rich and abundantpopulations of native plant andanimal species across a broad range of habitats. However, theenvironment is under serious threat, with approximately only 12% of native vegetation remaining and one in five native plant and animal species listed as being under threat of extinction.

Figure 1: Loddon Campaspe Irrigation Region – Native Vegetation, Waterways and Wetlands

Land Management

88% of the region is privately owned land used predominantly for agriculture. Management of private land is particularly important for biodiversity conservation. Private land supports 50% of the region's remaining native vegetation. In addition, agricultural activities impact biodiversity and water resources across the region.

Public land such as parks, forests, wetlands, river frontages, roads and road reserves make up approximately 12% of the LCIR. Large blocks of vegetation, such as Terrick Terrick NP, Leaghur SP and Gunbower SP, and wetlands, such as Boort Lakes, Kerang Wetlands and Gunbower Island, are very important for maintaining native plant and animal populations.

Plants and Animals

• Total Plants and Animals: 1830 (Native: 1367)
• Plant Species: 1416
• Native Plants: 978
• Threatened Plants: 149 (15% of native plants)
• Introduced Plants/Weeds: 438 (31% of plants)
• Animal Species: 414
• Native Animals: 389
• Threatened Animals: 98 (25% of native animals)
• Introduced Animals/Pests: 25 (6% of animals)

Waterways and Wetlands

The LCIR is internationally recognised for its wetlands, supporting a large number and diversity of valuable wetlands in a very small geographic area. The extensive waterways of the LCIR provide important linkages for plants and animals living in a very fragmented landscape. As well as supporting significant plants and animals, wetlands and waterways transport and filter water and cycle nutrients, thus underpinning the functioning of all natural ecosystems in the region.

Vegetation

The LCIR supports a diversity of native vegetation including River Red Gum forests, Black Box woodlands, Mallee woodlands, grasslands and wetlands.

From the Victorian native vegetation classification system (Ecological Vegetation Classes or EVCs), the dominant vegetation types in the region are Plains Grassland, Plains Woodland, Chenopod Grassland and Riverine Chenopod Woodland. However most of the native vegetation has either been cleared or highly degraded. 88% of the area either lacks vegetation or supports mostly exotic vegetation (see figures 2 and 3).

This extensive loss of native vegetation communities means that remaining habitats are very important.

Pre 1750s Vegetation Communites

Figure 2: Pre-1750 Vegetation Cover (EVCs) in the LCIR

Current Vegetation Communities

Figure 3: Current Vegetation Cover (EVCs) in the LCIR

Threats

The biodiversity of the LCIR faces many threats. Management of these threats is very important in slowing biodiversity loss and allowing the recovery of natural habitats. The main threats include habitat loss and fragmentation, salinity, altered water regimes, water quality decline, urban growth, inappropriate recreation, agricultural activities, pest plants and animals, changed fire regimes and climate change.

Habitat Loss and Fragmentation

Habitat loss remains one of the key agents for biodiversity decline within the region. Habitat loss has been caused by:

• clearing for agriculture and urban development;
• salinisation of soils and water;
• inappropriate grazing regimes;
• cultivation for cropping and irrigation;
• firewood collection and removal of tree branches;
• removal of wood debris from waterways.

This has resulted in habitat patches that support fewer species because they are more exposed to threats and less connected to other habitat patches for animal and plant movement and breeding.

Altered Hydrology and Water Quality Decline

Management of water for irrigation has changed natural water regimes. Input of salt, nutrients, sediment, chemical toxins and cold water into waterways and wetlands has reduced the water quality. Water underpins the functioning of the ecosystems in the LCIR and changes create significant impacts on the presence of plants and animals. The transition from seasonal to permanent systems has disadvantaged some species while benefiting others.

Pest Plants and Animals

Pest plants and animals are abundant in the LCIR due to vegetation disturbance and inappropriate land management. This has a major impact on native plants and animals from increased competition, increased predation and/or changed habitats.

Climate Change

Climate change will result in a much drier environment in the LCIR. This will change the range of plants and the animals they support. Building resilient and well connected vegetation communities will allow species to more easily migrate and adapt.

So, What Can We Do?

Protect remaining biodiversity values from threats. Fencing to manage grazing along with pest plant and animal control are arguably the most effective first steps. In this region the restoration of natural water regimes is also vitally important.

Enhance the quality of existing habitats. Reintroduce missing habitat elements such as logs and understorey shrubs and expand and reconnect small and isolated vegetation patches through revegetation and regeneration techniques.

Restore habitats in cleared areas by revegetation using indigenous (local native) species.

Protection, enhancement and restoration of native vegetation will help to sustain resilient populations of native plants and animals, provide more robust landscapes, buffer degrading processes, enhance agricultural production, and contribute to the social well-being of the community.

Acknowledgements

This note was developed from information in the Loddon Campaspe Irrigation Region Biodiversity Plan.

For more information please contact the Environment Team at the Department of Primary Industries, Kerang on (03) 54521266.

The advice provided in this publication is intended as a source of information only. Always read the label before using any of the products mentioned. The State of Victoria and its employees do not guarantee that the publication is without flaw of any kind or is wholly appropriate for your particular purposes and therefore disclaims all liability for any error, loss or other consequence which may arise from you relying on any information in this publication. Maps contain DPI/DSE–CGDL information © State of Victoria 2008.